I found this similar question but it is about finding hints in the digital file :how-to-identify-photoshop-edited-files.
I want to know if there is a way to do this without looking at the digital file, for example If I only have a print of that photo available.
What markers should I look out for in a photo, to indicate a photo has been edited or tampered with?
Note that I do not have any experience of photography. This is just a question out of curiosity!
Currently, without having a rich experience in retouching there is probably very little chance you'd be able to tell. Even RAW files are, in a very basic sense editable.
Here are some hints:
If you're looking at fashion photography, always be mindful of skin texture. Bad retouchers (trying to please clients) generally destroy skin texture but often forget about retouching the area between the upper eye-lashes and the eye-brows. Also, look for strands of hair which start in the head but suddenly disappear upon entering the face.
The colour of skin is often very difficult to replicate if major work has been done, zoom out to a reasonable distance and try see if you can differentiate areas of unnatural colour.
Inexperienced photographers tend to place a large emphasis on retouching a subject's eyes, pay careful attention to the pupils, irises etc. to see if contrast and brightness has been added. You can usually tell immediately if they look "too bright".
More generally, it is often easy to spot if major objects in an image have been replaced by the Content-Aware Tool/Clone Brush etc. Look for areas of repeated pattern. Any pattern, be it large or small, repeated is a dead give away.
Fake objects in an image generally have different light sources (Are you in a different Galaxy? Why are there two sources of sunlight?)
Fake objects in an image also generally don't maintain the same grain as the rest of the image. They also tend to not have the same blurriness/sharpness as their surroundings.
I'll add some more if I think of any. Hope this helps.
You would need to be familiar with photo editing techniques as well as limitations of camera equipment to be able to identify both what you would consider to be "photoshopped" as well as the signs of when it occurs. I'm fairly new to the game, but I can usually tell when an image has more dynamic range than is possible with camera equipment so maybe the sky's been swapped out (or at least the image was double exposed), or the light has changed directions or temperature, or if someone's skin is super smooth (that's an easy one; people have pores!), etc. You could maybe pick up a handful of telltale signs (HDR halos, for example), but it would only get you so far.
I've heard some people (National Geographic and some contests) that require submission of the original RAW files so that they can be compared to the result to identify images that have been altered beyond what they allow. This is necessary because people are becoming so good at photoshop that it is impossible to identify an altered image from looking at it.
